I am trying to edit the overworld sprites for gym leaders. The only problem is that I can't find the gym leaders' sprites to begin with. I've manage to replace Red's overworld sprite with a character of my own, which works great. Red as well as many of the NPC's are in gfx/sprites. But the gym leader sprites aren't in there with the others.

Am I just not looking hard enough?

EDIT: Wow, I'm an idiot. Unique Gym Leader sprites were only introduced in the second generation.